1. Field of the Invention
This invention relates to burn front position determination. More particularly, but without limitation thereto, this invention relates to an interferometer for measuring burn front position in a solid propellant by means of sound waves.
2. Description of the Prior Art
Several instruments have been developed for determining burn front position. These operate using electromagnetic radiation, such as the microwave flame front detector.
The present invention functions by utilizing sound waves rather than electromagnetic radiation and there are several advantages to this approach. The present invention, an ultrasonic interferometer, is capable of operating through materials which are opaque to electromagnetic radiation, for example graphite composite materials and steel. Additionally, there is a greater usable depth of penetration and the data generated is easier to analyze. The ultrasonic interferometer operates on a shorter wavelength than microwave flame front detectors currently in use and it requires no adjustments to be made during operation.